Means to prevent over-fusing

ABSTRACT

Terminal straps to which cartridge fuses are bolt or screw connected are provided with locating means which establish predetermined operative positions for a reject member securable to one or more of the terminal straps. When the reject member is not present, fuses of relatively high intermediate and low ratings may be mounted to the terminal straps. When the reject member is mounted in one of its operative positions, only the low rated fuse may be mounted to the terminal straps, and when the reject member is in another one of its operative positions, both the low and intermediate rated fuses may be mounted to the terminal straps, but high rated fuses may not be mounted thereto.

0 United States Patent 1111 3,599,174

| 72| Inventor Shnrdha Singh Dhaiiwal 2,943,295 6/1960 Stewart t. 339/258 F Sterling Heights, Mich. 3 1 79,772 4/1965 Summers 337/209 1 1 Appl No 843.065 3.198913 8/1965 Stunlmck 339/258 F X 12:: Filed July Primary E.\'am[ner1an A tilvert U Pmenmd 197,1 AssistantExaminer-Terrel1P Lewis I v H Amlgmge l'T'E Imperial torporauon A!t0rneyOstrolenk. Faber. Gerh and Soffen Philadelphia, Pa.

1541 MEANS TO PREVENT OVER-[ UBING l0 ('Iaims. 12 Drawing Figs.

1$s t.|tS.C|. v 339/125R, 33* /209337/225339/31 R.339/75 R. 339/253 rsawzscaawss P339 270? 5 i 1 Int. Cl. H02!) [[02, HOlr 11/22 H] Field of Search 339/3 l- 33 75, 34. 36, 37. 45.1i9,125,252 F, 253 Fv 256 F. 258 F.259 F. 262 F, 263 F.265 F, 266 F. 270; 337/209, 225,226

ABSTRACT: Terminal straps to WhlCh cartridge fuses are bolt or screw connected are pitmded with locating means which establish predetermined operative positions for a reject member securable to one or more of the terminal straps. When the reject member is not present fuses of relatively high intermediate and low ratings may he mounted to the terminal straps When the reject member is mounted in one of its operative positions, only the low rated fuse may be mounted to the terminal straps, and when the reject member is in another one of its operative positions, both the low and intermediate rated fuses may be mounted to the terminal straps. but high rated fuses may not he mounted thereto PATENTEU Ami: 0192: 3,599,174

E Ts 54 J;- .2. R25.

PATENTEU AUBIOIHTI I 3599-174 SHEET 2 or 3 w; JEE=5A BY MEANS TO PREVENT OVER-FUSING This invention relates to means for preventing overfusing, and more particularly relates to means of this type, especially adapted for use with fuses that are bolt or screw connected to terminal straps.

Cartridge fuses rated I amperes and higher are provided with blade-type terminals that may be bolt or screw connected to their terminal mounting straps. For one particular family or class of fuses in the current range of 600 to 2,000 amperes, the fuse with a 600 ampere rating is provided with relatively narrow and short terminal blades, the fuse with a 1,200 ampere rating is provided with relatively narrow and long terminal blades, while the fuse of 2,000 ampere rating is provided with terminal blades that are both relatively long and wide. In order to prevent overfusing of devices utilizing fuses of this class, the instant invention provides a blocking or reject member constructed of rigid material and having means for riveting or otherwise permanently securing the reject member to a terminal strap in different predetermined operative positions. In one operative position for the reject member, it is positioned adjacent to the side of the intermediate rated fuse blades to permit mounting thereof. However, the high rated fuse blades are so wide that the reject member in this position interferes with mounting of such fuse to the terminal straps. In another relative position for the reject member, it is positioned adjacent to the end of a terminal blade for the low rated fuse, and in this latter position the reject member prevents mounting of both the intermediate and high rated fuses, since their terminal blades are too long.

Accordingly, a primary object of the instant invention is to provide novel means to prevent overfusing.

Another object is to provide reject means for bolted or screwed fuses with ratings in excess of the rating for which the fused equipment is designed.

Still another object is to provide a terminal strap for the making of bolted or screwed-type fuse connections, with the terminal strap having formations to selectively choose the position ofa fuse reject member.

These objects as well as other objects of this invention will become readily apparent when reading the following description of the accompanying drawings in which:

FIG. 1 is an exploded perspective of a screwed-type cartridge fuse and terminal means therefor together with overfusing reject means constructed in accordance with teachings of the instant invention.

FIG. 2 is an enlarged side elevation of the reject member of FIG. 1.

FIGS. 2A and 2B are elevational views of the reject member, looking in the directions of the respective arrows .2A2A and 2B2B.

FIG. 3 is a fragmentary plan view showing the reject member mounted to a terminal strap.

FIG. 4 is a cross section taken through line 4-4 of FIG. 3, looking in the direction of arrows 4-4.

FIG. 5 is a plan view, with the terminal straps fragmented, showing the relationship of a relatively low rated fuse to the reject member when the latter is positioned to prevent mounting ofintermediate and high rated fuses.

FIG. 6 is a plan view, similar to FIG. 5, showing an intermediate rated fuse in relation to the reject member when positioned as in FIG. 5.

FIG. 6A is a cross section taken through line 6A-6A of FIG. 6, looking in the direction of arrows ISA-6A.

FIG. 7 is a plan view, similar to FIG. 6, with the reject member operatively positioned to permit mounting of an intermediate rated fuse.

FIG. 8 is a plan view, similar to FIG. 7, showing the relationship between a relatively high rated fuse and the reject member when positioned as in FIG. 7.

FIG. 8A is a cross section taken through lines 8A8A of FIG. 8, looking in the direction of arrows 8A-8A.

Now'referring to the figures, and more particularly to FIG. 1. Fuse mounting terminal straps 10, ll, constructed of good electrically conductive material such as copper or aluminum,

are'mounted in spaced relationship, being secured to insulating sheet 12 by screws 13 which extend through clearance apertures 14 in out-turned ears 15,16 ofeach strap 10 and l 1. Since straps 10 and 11 are of identical construction, only strap 10 will be described in detail.

More particularly, strap 10 includes legs 17, 18 extending forward from ears l5, 16, respectively. The forward ends of legs 17, 18 are connected to the central portion 19 of strap 10, at opposite ends thereof, and position portion 19 forward of ears l5, l6. Terminal straps 10, El. are electrically connected to the apparatus to be protected by welded, screwed or bolted connections (not shown). The central portion 19 of strap 10 is provided with a pair of tapped holes 21, 22 for receiving bolts or screws that electrically and mechanically secure any one of the fuses which are relatively low rated 23 (FIG. 5), intermediate rated 24 (FIG. 7), and high rated 25 (FIG. 8). As seen in FIG. 1, a pair of hex head screws 27 pass through clearance apertures 28 in each of the terminal blades 31, 32 projecting from opposite ends of fuse body 29 and are threadably received by holes 21, 22.

Central strap portion 19 is provided with a group of three apertures 41, 42, 43, proportioned to receive the legs 36, 37 of reject member 35 for a reason that will be hereinafter explained. As seen best in FIGS. 2, 2A and 2B, reject member 35 is constructed of rigid material, preferably being stamped from steel sheet stock. Legs. 36, 37 extend downwardly from main body portion 38 and are positioned at opposite sides thereof.

In FIGS. 3 and 4, legs 36, 37 are shown extending through apertures 41, 42, respectively, with free ends of legs 36, 37 having been peened over, or riveted, to fixedly secure reject member 35 to terminal strap 10. This is the position occupied by reject member 35 in FIGS. 7, 8 and 8A.

More particularly, with reject member 35 positioned as in FIG. 7, intermediate rated fuse 24 may be mounted to terminal straps l0 and 11. When intermediate fuse 24 is operatively mounted, reject member 35 is positioned adjacent to the side of fuse terminal blade 31. However, fuse terminal blades 31A, 32A (FIGS. 8 and 8A) are so much wider than fuse terminal blades 31, 32 that the terminal blades of high rated fuse 25 are prevented from assuming their operative positions adjacent to the forward surfaces of the central portion 19 of each terminal strap 10 and 11.

When reject member 3.5 is secured to terminal strap 10 with legs 36, 37 extending through apertures 41 and 43, as in FIGS. 5, 6 and 6A, only low rated fuse 23 may be operatively mounted to terminal straps iii and More particularly, terminal blades 31MB and 35223 of low rated fuse 23 are short enough so as not to engage reject ember 35 when the latter is operatively positioned to prevent mounting of intermediate and high rated fuses 24, 25. With reject member 35 positioned as in FIGS. 6 and 6A, terminal bla e 31 is so long that it engages reject member 35, thereby pi venting operative mounting of intermediate rated fuse 2 to rninal straps it and 11. Under these conditions, since the teminal blades of high rated fuse 25 extend as far as the termini: blades for intermediate rated fuse 24, high rated fuse 25 will also be rejected when reject member 35 is mounted as in FIG. 6.

Naturally, when reject member 35 is not mounted to ten minal strap 10, any of the fuses 23, 24 and 25 may be mounted to terminal straps N and 12.

Thus, it is seen that the instant reject member that may be seller. overfusing when using bolted Although there has been describe of this novel invention, many variat and modifications will now be apparent to those skiiled in an. art. Therefore, this invention is to be limited, not by the specific disclosure herein, but only by the appending claims.

The embodiments of the invention in which I claim an exclusive privilege or property are defined as follows:

a preferred embodiment 1. Fuse mounting means including a pair of straps for mounting relatively high, intermediate, and low rated fuses constituting a family of fuses in which each fuse includes a body having terminal blades protruding from opposite ends thereof with the blades of high rated fuses being wider than the blades of low and intermediate rated fuses, and the blades of low rated fuses being shorter than the blades of intermediate and high rated fuses; insulating means mounting said straps with a gap therebetween sufficiently long to accommodate the body of any fuse in the family of fuses when such fuse is operatively secured to said straps; securing means for mechanically and electrically connecting fuse blades to said straps; a first of said straps having first locating means for mounting a reject member to said first strap in a first operative position relative thereto; said first strap also having a second locating means for mounting a reject member to said first strap in a second operative position; said first locating means positioned so that a reject member in said first operative position permits operative securement of low and intermediate rated fuses to said straps while preventing operative securemerit of high rated fuses to said straps; said second locating means positioned so that a reject member in said second operative position permits operative securement of low rated fuses to said straps while preventing operative securement of intermediate and high rated fuses to said straps.

2. Fuse mounting means as set forth in claim 1, in which the securing means comprise screw type connections.

3. Fuse mounting means as set forth in claim 1, in which the securing means secure fuse blades to forward mounting surfaces of said straps and reject members when in their operative positions project forward of said forward mounting surface of said first strap.

4. Fuse mounting means as set forth in claim 3, in which said first strap includes a formation that is common to both said first and said second locating means.

5. Fuse mounting means as set forth in claim 4, including a reject member operatively secured to said first strap in one of said first and said second operative positions; said reject member including a main section projecting forward of a forward mounting surface of said first strap; said reject member also including a plurality of legs extending to the rear of said main section; each of said first and said second locating means including a plurality of apertures to receive said plurality of legs with one of said apertures constituting said formation.

6. Fuse mounting means as set forth in claim 5, in which said straps are constructed of a first material having relatively good electrical conducting properties and said reject member is constructed of a second material having relatively poor electrical conducting properties; said second material having stronger mechanical properties than said first material.

7. Fuse mounting means as set forth in claim 5, in which said first material is primarily copper or aluminum and said second material is steel.

8. Fuse mounting means as set forth in claim 5, in which said reject member is relatively rigid and is constructed of sheet material.

9. Fuse mounting means as set forth in claim 6, in which the main section is located adjacent to a side of an operatively secured fuse blade when said reject member is in said first operative position; said main section being located adjacent to the free end of an operatively secured fuse blade when said reject member is in said second operative position.

10. Fuse mounting means as set forth in claim 9, in which each of said straps includes mounting legs and a central portion positioned forward of said mounting legs; said securing means of said first strap including at least one screw-receiving tapped aperture extending through said central portion of said first strap; said locating means apertures extending through said central portion of said first strap. 

1. Fuse mounting means including a pair of straps for mounting relatively high, intermediate, and low rated fuses constituting a family of fuses in which each fuse includes a body having terminal blades protruding from opposite ends thereof with the blades of high rated fuses being wider than the blades of low and intermediate rated fuses, and the blades of low rated fuses being shorter than the blades of intermediate and high rated fuses; insulating means mounting said straps with a gap therebetween sufficiently long to accommodate the body of any fuse in the family of fuses when such fuse is operatively secured to said straps; securing means for mechanically and electrically connecting fuse blades to said straps; a first of said straps having first locating means for mounting a reject member to said first strap in a first operative position relative thereto; said first strap also having a second locating means for mounting a reject member to said first strap in a second operative position; said first locating means positioned so that a reject member in said first operative position permits operative securement of low and intermediate rated fuses to said straps while preventing operative securement of high rated fuses to said straps; said second locating means positioned so that a reject member in said second operative position permits operative securement of low rated fuses to said straps while preventing operative securement of intermediate and high rated fuses to said straps.
 2. Fuse mounting means as set forth in claim 1, in which the securing means comprise screw-type connections.
 3. Fuse mounting means as set forth in claim 1, in which the securing means secure fuse blades to forward mounting surfaces of said straps and reject members when in their operative positions project forward of said forward mounting surface of said first strap.
 4. Fuse mounting means as set forth in claim 3, in which said first strap includes a formation that is common to both said first and said second locating means.
 5. Fuse mounting means as set forth in claim 4, including a reject member operatively secured to said first strap in one of said first and said second operative positions; said reject member including a main section projecting forward of a forward mounting surface of said first strap; said reject member also including a plurality of legs extending to the rear of said main section; each of said first and said Second locating means including a plurality of apertures to receive said plurality of legs with one of said apertures constituting said formation.
 6. Fuse mounting means as set forth in claim 5, in which said straps are constructed of a first material having relatively good electrical conducting properties and said reject member is constructed of a second material having relatively poor electrical conducting properties; said second material having stronger mechanical properties than said first material.
 7. Fuse mounting means as set forth in claim 5, in which said first material is primarily copper or aluminum and said second material is steel.
 8. Fuse mounting means as set forth in claim 5, in which said reject member is relatively rigid and is constructed of sheet material.
 9. Fuse mounting means as set forth in claim 6, in which the main section is located adjacent to a side of an operatively secured fuse blade when said reject member is in said first operative position; said main section being located adjacent to the free end of an operatively secured fuse blade when said reject member is in said second operative position.
 10. Fuse mounting means as set forth in claim 9, in which each of said straps includes mounting legs and a central portion positioned forward of said mounting legs; said securing means of said first strap including at least one screw-receiving tapped aperture extending through said central portion of said first strap; said locating means apertures extending through said central portion of said first strap. 